<ExtensionAttribute> _
Public Shared Function First(Of TSource) ( _
    source As IEnumerable(Of TSource), _
    predicate As Func(Of TSource, Boolean) _
) As TSource

Dim source As IEnumerable(Of TSource)
Dim predicate As Func(Of TSource, Boolean)
Dim returnValue As TSource

returnValue = source.First(predicate)

public static TSource First<TSource>(
    this IEnumerable<TSource> source,
    Func<TSource, bool> predicate
)

[ExtensionAttribute]
public:
generic<typename TSource>
static TSource First(
    IEnumerable<TSource>^ source, 
    Func<TSource, bool>^ predicate
)

JScript does not support generic types or methods.

Usage Note

The First<(Of <(TSource>)>)(IEnumerable<(Of <(TSource>)>), Func<(Of <(TSource, Boolean>)>)) method throws an exception if no matching element is found in source. To instead return a default value when no matching element is found, use the FirstOrDefault method.

The following code example demonstrates how to use First<(Of <(TSource>)>)(IEnumerable<(Of <(TSource>)>), Func<(Of <(TSource, Boolean>)>)) to return the first element of an array that satisfies a condition.

' Create an array of integers.
Dim numbers() As Integer = _
    {9, 34, 65, 92, 87, 435, 3, 54, 83, 23, 87, 435, 67, 12, 19}

' Select the first element in the array whose value is greater than 80.
Dim first As Integer = numbers.First(Function(number) number > 80)

' Display the output.
MsgBox(first)

' This code produces the following output:
'
' 92

int[] numbers = { 9, 34, 65, 92, 87, 435, 3, 54, 
                    83, 23, 87, 435, 67, 12, 19 };

int first = numbers.First(number => number > 80);

Console.WriteLine(first);

/*
 This code produces the following output:

 92
*/

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

.NET Framework

.NET Compact Framework

XNA Framework

Reference